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Backward Sea Ice Drift Trajectories Recent studies have indicated that drifting Arctic sea ice plays an important role in the redistribution of sediments and contaminants in the world's waterways. Contaminants are also transported into the Arctic by air masses and ocean currents and they affect the entire Arctic ecosystem. To monitor sea ice drift effectively, ice motion vectors derived from satellite data are required; from this data it is possible to simulate backward trajectories to determine the origin of the sea ice. The shallow waters of the marginal seas are a key region where this process takes place as contaminants are commonly found in coastal waters. The physical and chemical mechanisms responsible for contaminant entrainment are also most active in turbid coastal waters. These substances are discharged in areas where the drifting sea ice meets warmer currents and melts. The Norwegian Polar Institute (NPI) produces yearly backward trajectories for monitoring purposes based on the ice drift vectors provided by the Institut Français de Recherche pour l'Exploitation de la MER (IFREMER). These backward trajectories will allow scientists to determine the source of sea ice in the marginal ice zone of the Barents Sea.
IFREMER produces ice motion vectors during the winter months (October to April) as a product for the Polar View baseline portfolio. The motion vectors are derived on a 3 and 6-day frequency from the combination of QuikSCAT and SSM/I data. For each chosen point along the ice edge in the Barents Sea, backward trajectories are calculated to their position at the beginning of the previous October. In addition, several points within the Barents Sea ice pack are chosen, and backward trajectories are calculated. Thus, for simulation of ice transport and subsequent statistical analysis, 3-day average maps of sea ice drift fields and sea ice concentration are produce on the same grid. As the time series grows, a variety of users will benefit from backward trajectory data to use as a tool for statistical analyses with respect to design and location of offshore installations and activities.
IFREMER produces ice motion vectors during the winter months (October to April) as a product for the Polar View baseline portfolio. The motion vectors are derived on a 3 and 6-day frequency from the combination of QuikSCAT and SSM/I data.
You will note that the grid starts at the beginning of the winter and moves across the map towards the Fram strait as the winter season progresses. Thanks to satellite measurements, using QuikSCAT and SSM/I, the sea-ice drift can be estimated over a winter season (2005-2006 is shown here). Canada is on the left, Russia in the right, Greenland at the bottom. The ice-free ocean is depicted in white. First year sea-ice is shown in blue, (it is less thick); it drifts more quickly than multi-year ice (red, yellow and green). Thicker ice can be seen in northern Canada. A mixture of single and multi-year ice concludes its passage through the Arctic Ocean by "descending" to warmer latitudes, picking up speed through the Fram Strait (East of Greenland). |
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